Progressive symmetric erythrokeratoderma (PSEK) is a rare heterogeneous genodermatoses characterized by early onset of well-defined, fixed erythematous and hyperkeratotic plaques usually affecting the extensor surface of extremities, buttocks, and sometimes face, sparing the truncal area.[1] To our knowledge, less than 100 cases have been described in the English literature.[2] Here, we report a rare presentation of PSEK associated with punctuate palmoplantarkeratoderma in a 10-year-old girl with no affection of family members.

A 10-year-old girl presented with asymptomatic erythematous lesions on her extremities and palmoplantar thickening since her early childhood. The lesions present on extensor surfaces started as erythematous, scaly macules progressing into slightly hyperkeratotic plaques covering more areas but were not migratory in nature. Her developmental milestones were normal. The child was born out of nonconsanguineous marriage, and none of her family members had similar lesions.

On cutaneous examination, there were well-defined, erythematous, hyperkeratotic, scaly, plaques symmetrically distributed over the dorsa of fingers and knuckles, knees, and dorsa of feet including toes [Figure 1]a and [Figure 1]b. Palmar lesions were seen as multiple round, keratotic, punctate lesions on palmar creases and hypothenar skin [Figure 2]a. Such lesions were also present on plantar surface, predominantly over pressure-prone areas. Many of these punctate keratotic lesions present on heel merged to form larger lesions [Figure 2]b. The mucocutaneous examination of other sites was normal. Systemic examination was unremarkable and routine laboratory parameters were within normal limits.

Figure 1: (a) Well-defined, erythematous, mildly hyperkeratotic, scaly, plaques on dorsa of fingers and knuckles, as well as knees. (b) Similar erythematous, hyperkeratotic, scaly plaques affecting the dorsa of feet including toes

Clinical and histopathological features were consistent with the diagnosis of PSEK with probably autosomal recessive mode of inheritance. Genetic analysis could not be done due to unavailability of resources in our hospital. Topical keratolytics, emollients, and oral vitamin A were started, but the patient did not turn up for further evaluation.

“Erythrokeratodermas” are a group of rare genodermatosis which includes two major nonsyndromic entities –progressive symmetric erythrokeratoderma (PSEK) and erythrokeratoderma variabilis (EKV) – and some syndromes such as KID (keratitis, ichthyosis, deafness) syndrome and HID (hystrix-like ichthyosis withdeafness) syndrome.[3] Although PSEK was first described by Darier, the term was coined by Gottron, hence eponymically also known as “Darier–Gottron syndrome.”[4]

Most cases of PSEK follow an autosomal dominant mode of inheritance with incomplete penetrance and variable expressivity, however, sporadic cases do occur frequently and few autosomal recessive cases have also been reported (as in our case). The molecular basis of PSEK is still obscure with no confirmed candidate gene. Of note, in a single case of PSEK, mutation in GJB4 gene encoding connexin 30.3 protein (often seen in cases of EKV) was found.[5] No genetic mutation was identified in all other cases.[6],[7],[8]

The classical presentation of PSEK consists of symmetrically distributed, nonmigratory, large, well-defined, erythematous, hyperkeratotic plaques with marked peripheral erythema.[1] The sites of predilection are extensors of extremities and sometimes face.[1] The trunk is usually spared. Mostly, PSEK has infantile or childhood onset with no gender predilection. The lesions progress slowly during childhood and tend to stabilize during teenage years.[2]

The histopathological features of PSEK are orthokeratotic hyperkeratosis, focal parakeratosis, mild or moderate acanthosis, normal or prominent granular layer, and perivascular lymphocytic infiltration in papillary dermis.[3]

EKV, psoriasis, and pityriasis rubra pilaris are close differential diagnosis of PSEK.[3] The latter two entities can easily be ruled out by clinical and histopathological evaluation. The clinical, histological, and genetic overlapping between EKV and PSEK questioned their separate existence. Consequently, an alternative term EKV progressiva was suggested in past years in place of PSEK and EKV.[9] Whatever be the different school of thoughts, this dispute can only be puzzled out with reporting of more cases and their genetic studies. Till then, it is reasonable to know the existing distinguishable features between the two, which are summarized in [Table 1].

PSEK has been reported to be associated with PPK and many other conditions.[3] In our case, it was interesting to find the punctate type of PPK which also involved palmar creases. Of note, we have not been able to find any case of PSEK in previous literature which had this association. Reporting of such cases widen the clinical spectrum of PSEK and lessen the chances of misdiagnosis and the urge of correlating with a syndrome.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.